The Collaborative International Dictionary of English v.0.48:

Fourteenth \Four"teenth`\, a. [Cf. OE. fourtende, fourtethe, AS.
   fe['o]werteo[eth]a.]
   1. Next in order after the thirteenth; as, the fourteenth day
      of the month.
      [1913 Webster]

   2. Making or constituting one of fourteen equal parts into
      which anything may be divided.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fourteenth \Four"teenth`\, n.
   1. One of fourteen equal parts into which one whole may be
      divided; the quotient of a unit divided by fourteen.
      [1913 Webster]

   2. (Mus.) The octave of the seventh.
      [1913 Webster]

   3. One next after the thirteenth in a series.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fourteenth
    adj 1: coming next after the thirteenth in position [syn:
           fourteenth, 14th]
    n 1: position 14 in a countable series of things